This application pertains to the art of ski grinding, and more particularly to a holding device for a snow ski for improved ski grinding. The invention is particularly applicable to be used with an automatic ski grinding machine and will be described with particular reference thereto. However, it will be appreciated that the invention has broader applications and could be used with a hand grinding device or advantageously employed in other environments and applications.
After a ski has been in use for a certain amount of time the bottom runner and the edges of the ski acquire gouges, scrapes, and nicks which damage the integrity of the ski. Such gouges, scrapes and nicks on the bottom runner of the ski destroy the smoothness of the bottom. The bottom should be smooth to allow for a more frictional-less contact between the snow and the runner thereby allowing greater speed and more responsive control. Additionally, damage to the edges of the ski diminishes the responsiveness of the ski when a skier attempts to make turns and stops.
In order to regain the integrity of the ski by recreating a smooth bottom surface and removing the nicks and scrapes from the edges of the ski, skiers will typically have these sections of the ski ground and sharpened to acquire the desired smoothness on the bottom of the ski and the sharpness on the edges.
A typical present method for grinding of skis employs a stone grinder with a foot pedal and a drive wheel so that the weighted drive wheel drags the ski across the stone. An alternative method for sharpening is simply having a grinding stone and a person who is grinding to hold the ski in his or her hands and by eyesight re-sharpen the ski's edges.
When using a stone grinder with a drive wheel to drag the ski across the stone, the drive wheel must make contact with the ski. Direct contact to the top of the ski is not desirable due to the damage the drive wheel would cause to the bindings which are located on the top portion of the ski. Therefore, some sort of holding device must be employed to allow the drive wheel to move the ski without directly touching the ski.
Heretofore various methods have been implemented in an attempt to allow the drive wheel to move the ski absent directly contacting the ski. One method includes putting a ramp-type frame on top of the ski so that the area underneath the ramp includes the ski bindings. This allows the drive wheel to move the ski and at the same time avoid damaging the bindings.
A major drawback to this type of method is that the cross-feed of the ski is not constant. The cross-feed is the rate at which the ski is pulled from its front portion or tip through the grinding machine until it reaches its end portion or tail. Excessive grinding occurs when the drive wheel is moving up and down the ramp, as it takes more time to cover the horizontal area beneath the ramp than the horizontal areas not beneath the ramp because the drive wheel simple has to go farther while going up and down the ramp than the grinding wheel has to go across the opposed flat ski surface. This excessive grinding creates scallops in these areas, thereby destroying the complete smoothness of the ski.
The problem with a non-constant cross-feed has been addressed by another method. This method includes using a straight edge in a parallel feed system. The operator of the grinder simply lays a straight edge on a ski and holds the ski and straight edge together when feeding the ski into the machine. Such a method eliminates scallops caused by inconsistent cross-feeds. While cross-feed is controlled by the rate that the feeder wheel pulls the ski through the grinder, in-feed of a ski is controlled by weighing the drive wheel onto the ski. In-feed is the amount of material that is removed by bringing the wheel to the ski or ski to the wheel and is usually controlled by weight and not by a specific amount. In other words, by applying a selected weight to the wheel, the resulting pressure will cause some amount of the ski surface to be removed. Since the straight edge is in no way hooked or fastened to the ski and the ski itself is not straightened out, problems with in feed control will persist.
Specifically, since weight controls the in-feed to the grinding wheel and the width of the ski changes from tip to tail, the amount of in-feed will vary with the width of the ski, thus varying in-feed. By not being positively attached to the ski, the straight edge or ramp mechanism will have a tendency to chatter and slide thereby causing non-uniformed pressure from the drive wheel to be transferred down to the ski.
Additionally, each ski contains an inherent camber to its form and such camber is destroyed or altered when either of the above-mentioned holding methods are used since neither of the methods completely flatten or decamber the ski to be ground. The present methods are simply concerned with making the ski flat from edge to edge. No consideration is given to making the ski smooth from edge tip to edge tail.
Consequently, a need exists for improvements in the holding of a ski to be reground which will result in greater reliability in control of cross-feed, in-feed, and decambering of a ski's normal structure thereby allowing a ski to be refinished with the ski bottom being smooth edge to edge and tip to tail and for accurate sharpening of ski's edges, while at the same time maintaining the original camber of the ski.